1. Field of the Invention
The invention relates to data compression and decompression particularly with respect to processing short records.
2. Description of the Prior Art
The prior art is exemplified by U.S. Pat. No. 4,464,650; issued Aug. 7,1984; entitled "Apparatus And Method For Compressing Data Signals And Restoring The Compressed Data Signals"; by Eastman et al. and by U.S. Pat. 4,558,302; issued Dec. 10, 1985; entitled "High Speed Data Compression And Decompression Apparatus And Method"; by Welch. Said U.S. Pat. Nos. 4,464,650 and 4,558,302 are incorporated herein by reference in their entirety. The systems of said U.S. Pat. Nos. 4,464,650 and 4,558,302 are practical implementations of Lempel-Ziv data compression and represent the state of the art in this technology.
The data compression and decompression systems of said U.S. Pat. Nos. 4,464,650 and, 5,558,302 have a disadvantage which limits the usefulness thereof in certain applications. In order to decompress any section of compressed data, it is necessary first to decompress any and all data which precedes the desired section of data in the original input file. This process can be slow and cumbersome in applications where frequent access to individual records of a file is required. Heretofore it has not been possible to retrieve and decompress individual records from a file without having to decompress preceding records in the file. Additionally, the prior art did not provide the capability of decompressing an individual record, altering the record and recompressing the altered record without having to decompress and recompress the preceding records in the file.